title: Feasibility study on the potential of a spiral blade in osteoporotic distal femur fracture fixation.
abstract: BACKGROUND
  Osteoporotic fractures of the distal femur (primary as well as periprosthetic) are a growing problem in today's trauma and orthopaedic surgery. Therefore, this feasibility study should identify the biomechanical potential of a (commercially available) spiral blade in the distal femur as compared to a single screw without any additional plate fixation. Additionally, the influence of cement augmentation was investigated.
  
  
  METHODS
  An artificial low density bone model was either instrumented with a perforated spiral blade or a 5 mm locking screw only. Additionally, the influence of 1 ml cement augmentation was investigated. All specimens were tested with static pull-out and cyclic loading (50 to 250 N with an increment of 0.1 N/cycle).
  
  
  RESULTS
  In the non-augmented groups, the mean pull-out force was significantly higher for the blade fixation (p < 0.001). In the augmented groups, the difference was statistically not significant (p = 0.217). Augmentation could increase pull-out force significantly by 72 % for the blade and 156 % for the screw, respectively (p = 0.001). The mean number of cycles to failure in the non-augmented groups was 12,433 (SD 465) for the blade and 2,949 (SD 215) for the screw, respectively (p < 0.001). In the augmented group, the blade reached 13,967 (SD 1,407) cycles until failure and the screw reached 4,413 (SD 1,598), respectively (p < 0.001).
  
  
  CONCLUSIONS
  The investigated spiral blade was mechanically superior, significantly, as compared to a screw in the distal femur. These results back up the further development of a distal femoral blade with spiral blade fixation for the treatment of osteoporotic distal femur fractures.
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Albert Schweitzer Campus 1, Buildung W1, 48149, Munster, Germany, Dirk.waehnert@ukmuenster.de.
authors.forename: D
authors.initials: D
authors.lastname: Wähnert
authors.forename: L
authors.initials: L
authors.lastname: Hofmann-Fliri
authors.forename: M
authors.initials: M
authors.lastname: Götzen
authors.forename: C
authors.initials: C
authors.lastname: Kösters
authors.forename: M
authors.initials: M
authors.lastname: Windolf
authors.forename: M J
authors.initials: MJ
authors.lastname: Raschke
mesh_terms: D001696:Biomechanical Phenomena; D005240:Feasibility Studies; D005264:Femoral Fractures / Q000503:physiopathology / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006801:Humans; D058866:Osteoporotic Fractures / Q000503:physiopathology / Q000601:surgery*